#version 430
uniform float offset;

void main(void)
{
    if(gl_VertexID == 0) {
        gl_Position = vec4(0.25 + offset, -0.25, 0.0, 1.0);
    } else if(gl_VertexID == 1) {
        gl_Position = vec4(-0.25 + offset, -0.25, 0.0, 1.0);
    } else {
        gl_Position = vec4(0.25 + offset, 0.25, 0.0, 1.0);
    }
}